transformer

American  

[trans-fawr-mer] / trænsˈfɔr mər /

noun

1. a person or thing that causes or undergoes a change in appearance, structure, character, etc.

2. Electricity. an electric device consisting essentially of two or more windings wound on the same core, which by electromagnetic induction transforms electric energy from one set of one or more circuits to another set of one or more circuits such that the frequency of the energy remains unchanged while the voltage and current usually change.

3. Computers. Also transformer model a type of neural network that uses statistical relationships between sequential data, such as words and sentences, to learn context and produce output.

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transformer British  

/ trænsˈfɔːmə /

noun

1. a device that transfers an alternating current from one circuit to one or more other circuits, usually with an increase ( step-up transformer ) or decrease ( step-down transformer ) of voltage. The input current is fed to a primary winding, the output being taken from a secondary winding or windings inductively linked to the primary

2. a person or thing that transforms

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transformer Scientific  

/ trăns-fôr′mər /

1. A device used to change the voltage of an alternating current in one circuit to a different voltage in a second circuit, or to partially isolate two circuits from each other. Transformers consist of two or more coils of conducting material, such as wire, wrapped around a core (often made of iron). The magnetic field produced by an alternating current in one coil induces a similar current in the other coils.

2. ◆ If there are fewer turns on the coil that carries the source of the power than there are on a second coil, the second coil will provide the same power but at a higher voltage. This is called a step-up transformer.

3. ◆ If there are fewer turns on the second coil than on the source coil, the outgoing power will have a lower voltage. This is called a step-down transformer.

4. Compare converter rectifier

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transformer Cultural  

1. A device used to transfer electrical energy from one circuit to another. With an alternating current, a transformer will either raise or lower the voltage as it makes the transfer.

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Etymology

Origin of transformer

First recorded in 1595–1605; transform + -er ¹

Explanation

Use the noun transformer when you're talking about a device that conducts electricity and controls the voltage that can travel between one circuit and another. Electricians are familiar with transformers, since they are commonly used to manage the voltage of electricity that powers houses and some businesses. Sometimes you can see a transformer attached to a utility pole on a residential street. The word transformer was coined in 1883 from the French transformateur, which in turn comes from the Latin transformare, "change the shape or form of." The prefix trans, or "across or beyond," gives a clue to this meaning.

Example Sentences

Utilities facing surging loads from AI campuses are competing for limited transformer supply.

From MarketWatch • Apr. 8, 2026

The industry is also scrambling for labor: transformer manufacturing is skilled and labor intensive, with apprenticeship programs that can take nine to 12 months.

From Barron's • Mar. 2, 2026

On a recent day, a group of emergency energy engineers gathered at a transformer substation to carry out repairs after residents turned on all their equipment at once when power was restored, overloading the system.

From The Wall Street Journal • Feb. 15, 2026

The game was supposed to be played Friday night along with the full slate of City Section contests, but it was postponed until Monday afternoon after a transformer problem left the school without power.

From Los Angeles Times • Nov. 18, 2025

Lately I was hypersensitive to touch and even someone else combing my hair or scratching my back felt like a transformer blowing up under my skin.

From "The Line Tender" by Kate Allen

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